1. Technical Field
The present invention relates generally to an apparatus and method for remotely deleting critical information and, more particularly, to an apparatus and method that are capable of remotely deleting critical information using a physically unclonable function (PUF).
2. Description of the Related Art
In cryptosystem installed in mobile terminals, critical information including a number of keys, such as a master key, a wrap key, a session key, etc., is used. This critical information necessitates the function of deleting it if necessary in the event of a case in which the mobile terminal equipped with the cryptosystem is lost.
In general, in order to remotely delete information in a server-client environment, a server, that is, the agent of the deletion, should broadcast a deletion command. In this case, transmitter authentication that is performed by the server is essential. If the server, that is, a transmitting side, is not authenticated, a mobile terminal that has received the deletion command cannot verify the agent that has transferred the deletion command. That is, if the transmitting side is not authenticated, an attacker may delete critical information by generating a deletion command message and transferring the deletion command to a specific mobile terminal. This means that the entire system of the mobile terminal is susceptible to an unexpected serious threat.
Currently, a method that includes the identity of a deletion target in a deletion command, signs the command with a digital signature, and broadcasts the command is chiefly used as transmitter authentication technology. In this case, if the identity of the deletion target is regarded as critical information, additional symmetric key encryption is used to provide confidentiality.
Accordingly, in order to remotely delete critical information, the current method necessitates public key encryption. Meanwhile, in order to apply public key encryption, an infrastructure referred to as a Public Key Infrastructure (PKI) is required. In practice, it is difficult to use the method in an environment in which a PKI has not been established.
Meanwhile, Korean Patent Application Publication No. 10-2012-0059587 discloses a method in which, in the transition of the state of a finite state machine (FSM) inside an integrated circuit, there are a variety of subsequent states. Furthermore, this method allows a transition target state to be determined by the output of the PUF of a chip, an event generator, and a separate control logic.
That is, in the method disclosed in Korean Patent Application Publication No. 10-2012-0059587, information is input from the outside to the event generator as an input that is used for the transition of the state of the FSM inside the integrated circuit. Event information that is output by the event generator is input to a PUF, the PUF receives the event information and outputs predetermined output data, and the output data is processed by the control logic.
Since this PUF is not a mathematical function, a fuzzy extractor is additionally applied to the output value of the PUF in most of methods using PUFs. In this case, additional data, such as helper data, and an error correction code are also required.